Coming up, Sean Colvin's modern folk music in NPR studios. But first, it was Agatha Christie's most puzzling mystery: the case of the 11 missing days. Not even Marple or Poirot could sold solve this one, because the famous mystery writer never penned this perplexing predicament. She lived it.

In 1926, Christie disappeared. Her car was found abandoned in a quarry. Eleven days later, she was found in a spa hotel in Harrogate with no recollection of who she was. Now a new biography offers a fascinating explanation of what happened. The book is Agatha Christie: The Finished Portrait.

Dr. NORMAN: To understand what happened, one has to understand Agatha's mental state just prior to her disappearance. She kissed goodbye to her daughter, Rosalind, at about 10:00 o'clock that night, knowing that her husband was being unfaithful and was away for the weekend.

SEABROOK: Ooh.

Dr. NORMAN: And then she made various journeys. Police found her car practically hanging over the edge of a quarry quite near her home. She just disappeared. There was no sign of her. All her clothes and belongings were scattered around, including a thick fur coat; and it was a winter's night, but she didn't take it. The car was in a state of dishevelment. And she confessed that she'd had a severe bump on the head.

SEABROOK: So what is it that you say caused her to disappear these 11 days?

Dr. NORMAN: I think you have to distinguish here between amnesia from the bump on the head, which causes a person to lose their memory, just as she did; but the amnesiac will go around trying to find out who they are, where they are. She didn't behave like that at all. She'd...

SEABROOK: Oh, I see. So you argue she didn't have amnesia. She had...

Dr. NORMAN: Psychogenic fugue syndrome.

SEABROOK: Explain what that is.

Dr. NORMAN: Well, the person in a fugue, there's a loss of memory for long periods of their life, and also a loss of identity. And the person will tend to wander away from their normal surroundings; otherwise they behave fairly normally. And when she was up at Harrogate Hydro Hotel during the 11 missing days, she was playing the piano and singing, going to the library and reading the newspaper.

SEABROOK: Had she checked in under an assumed name or did she know her name?

Dr. NORMAN: She didn't know her name and she didn't recognize herself in the newspaper. She didn't even recognize her own photograph in the papers. She checked in under the name of Neele, N-E-E-L-E, and that was the surname of her husband's mistress. But she changed the Christian name to Teresa instead of Nancy.

SEABROOK: And what does it take to get a fugue state? I understand that these are much more well documented today.

Dr. NORMAN: They are indeed. We now know, with modern psychiatric knowledge, that a person goes into a fugue and attempt to escape from an intolerable situation. Her home was the most important part of her life, and you can see that when she could see the destruction of her married home, the loss of Archie, her husband, who she loved, she deliberately drove this car, as she thought, over the quarry. Now, in her autobiography she describes the two most important things that ever happened to her in her life as buying her Morris Cowley motorcar and meeting Her Majesty the Queen. So for her to attempt to destroy the car was a huge step.

SEABROOK: She went on - this happened fairly early in her career. She went on to write some of her most well-known mysteries. Did it ever recur? I mean did she just snap out of it and that was the end?

Dr. NORMAN: It never recurred, but it left her with a terrible feeling that there was something missing from her memory. Years later, in her late life, she visited the Regis Professor of Pastoral Theology at Oxford, who had a reputation for being a bit of a psychologist, in the hope of filling in these missing pieces of the jigsaw puzzle. But I'm afraid even he wasn't able to help her.

SEABROOK: Dr. Andrew Norman is the author of Agatha Christie: The Finished Portrait. Thank you so much.

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